This week's featured Iowa wildflower is native to most of North America east of the Rocky Mountains and typically grows in wet habitats, including roadside ditches as well as higher-quality wetlands.
I took all of the enclosed photos of Common boneset (Eupatorium perfoliatum) near the Windsor Heights bike trail, behind the Iowa Department of Natural Resources building on Hickman Road.
As a bonus, I've included at the end of this post some pictures of goldenrods with bizarre leaf clusters. I found them growing in Colby Park, near the other end of the Windsor Heights trail. Naturalist and photographer Leland Searles told me the strange foliage comes from a disease called aster yellows. Caused by a "bacterium-like organism called a phytoplasma," aster yellows can affect some 300 different species, including common food crops and garden plants. Experts recommend removing infected plants as soon as possible, so keep that in mind if you see signs of aster yellows in your yard.
Several species of boneset and some other native plants like white snakeroot have similar-looking small white flowers. The leaves and stems help me distinguish common boneset from other plants with the same kind of blossoms. The stems are hairy, and the leaves have a velvety texture. Where the leaves meet the stem, "it appears the stem grows through one large leaf," which inspired the Latin name perfoliatum (same root as "perforate").
You can see the stem and leaves in this shot of a common boneset plant that's jut starting to bloom.
Common boneset has long had a reputation as an effective herbal remedy for many conditions when dried and brewed into tea. As the plant's English name indicates, boneset leaves were also thought to aid the healing of broken bones.
Closer views of flowering common boneset plants:
Here's common boneset in the foreground. The taller plant that's not quite blooming is a different species, I think late boneset. The yellow flowers in the background are common sneezeweed; the bluish purple flowers are great blue lobelia.
More common boneset with sneezeweed and blue lobelia in the background.
Common boneset with great blue lobelia and black-eyed Susans to the left. A late boneset plant with reddish stems is growing on the right.
According to the Illinois Wildflowers page on common boneset,
The nectar or pollen of the flowers attracts many kinds of insects, including bees, flies, wasps, butterflies, and beetles. In particular, many kinds of unusual flies and wasps are attracted to the flowers because of the accessibility of the nectar. The caterpillars of various moth species are known to feed on various parts of Common Boneset, including Haploa clymene (Clymene Moth), Phragmatobia lineata (Lined Ruby Tiger Moth), Papaipema cataphracta (Burdock Borer Moth), Schinia trifascia (Three-Lined Flower Moth), Chlorochlamys chloroleucaria (Blackberry Looper Moth), and Semiothisa continuata (Geometrid Moth sp.).
I've seen lots of insects crawling on or flying near common boneset. I have no idea what this one is.
Here are the goldenrod plants infected by aster yellows.
The infection is harder to see on this plant, because goldenrod flowers are growing out of the strange cluster. I think the taller plants in the background (with white flowers about to bloom) are late boneset.